In some instances, a user may desire to extract a portion of an encoded image. For example, a JPEG-encoded image includes a picture of a child's art work. The picture is sent to the grandparents. The grandparents may want to extract the child's art work from the encoded image. In another example, an encoded image may include multiple people. A user may want to extract a portion of the image that includes a particular person.
In these instances, to extract the desired portion of the encoded image, typically, the entire image must be decoded and stored in a buffer. Many devices, such as cellular phones, personal digital assistants, etc., have limited memory. As a result, the requirement of decoding an entire image and storing the entire decoded image in a buffer for extracting a desired portion of the image may not allow these devices of limited memory to perform this function. This is undesirable, because users of devices, such as cellular phones or other portable devices, tend to like having the same functionality on their portable devices as they have with their personal computers.